Method of manufacturing press-formed product, apparatus for transporting heated workpiece, and hot-press manufacturing line

A method of manufacturing a press-formed product comprising:

• a heating step in which at least two sheet-shaped workpieces are simultaneously heated by a heating device;
• a transportation step in which the at least two heated workpieces heated at the heating step are transported by a transportation apparatus to a press machine;
• and
• a pressing step in which the at least two heated workpieces transported to the press machine at the transportation step are processed by the press machine,
• the transportation step including:
• driving a pair of first arms rotatably mounted on a base frame included in the transportation apparatus to cause claws of the pair of first arms to support a lower surface, at both ends, of a first heated workpiece of the at least two heated workpieces and lift the first heated workpiece;
• driving, using a system separate from that for the pair of first arms, a pair of second arms rotatably mounted on the base frame included in the transportation apparatus to cause claws of the pair of second arms to support a lower surface, at both ends, of a second heated workpiece of the at least two heated workpieces and lift the second heated workpiece;
• transporting the first heated workpiece with the lower surface supported, at both ends, by the claws of the pair of first arms of the transportation apparatus and the second heated workpiece with the lower surface supported, at both ends, by the claws of the pair of second arms, where the first and second heated workpieces overlap each other in a direction normal to a sheet surface of the first heated workpiece;
• driving the pair of first arms to lower the first heated workpiece supported by the pair of first arms to a pressing location on the press machine;
• and
• driving the pair of second arms using the system separate from that for the pair of first arms to lower the second heated workpiece supported by the pair of second arms to a pressing location on the press machine.